Add cookie support

©! I, Hugo Landau <hlandau@devever.net>, hereby licence these changes under the
©! licence with SHA256 hash
©! fd80a26fbb3f644af1fa994134446702932968519797227e07a1368dea80f0bc.

backend/backend.go

@@ -31,13 +31,6 @@ var log, Log = xlog.New("ncdns.backend")
 type Config struct {
 	NamecoinConn namecoin.Conn
 
-	// Username and password to use for connecting to the Namecoin JSON-RPC interface.
-	//RPCUsername string
-	//RPCPassword string
-
-	// hostname:port to use for connecting to the Namecoin JSON-RPC interface.
-	//RPCAddress string
-
 	// Maximum entries to permit in name cache. If zero, a default value is used.
 	CacheMaxEntries int
 

namecoin/namecoin.go

@@ -1,13 +1,15 @@
 package namecoin
 
 // btcjson had to be modified a bit to get correct error reporting.
-import "github.com/hlandauf/btcjson"
-import "gopkg.in/hlandau/madns.v1/merr"
-import extratypes "github.com/hlandau/ncbtcjsontypes"
+import (
+	extratypes "github.com/hlandau/ncbtcjsontypes"
+	"github.com/hlandauf/btcjson"
+	"gopkg.in/hlandau/madns.v1/merr"
 
-import "fmt"
-import "expvar"
-import "sync/atomic"
+	"expvar"
+	"fmt"
+	"sync/atomic"
+)
 
 var cQueryCalls = expvar.NewInt("ncdns.namecoin.numQueryCalls")
 var cSyncCalls = expvar.NewInt("ncdns.namecoin.numSyncCalls")
@@ -27,7 +29,29 @@ func newID() int32 {
 type Conn struct {
 	Username string
 	Password string
-	Server   string
+
+	// If set, this is called to obtain the username and password instead of
+	// using the Username and Password fields.
+	GetAuth func() (username, password string, err error)
+
+	Server string
+}
+
+func (nc *Conn) getAuth() (username string, password string, err error) {
+	if nc.GetAuth == nil {
+		return nc.Username, nc.Password, nil
+	}
+
+	return nc.GetAuth()
+}
+
+func (nc *Conn) rpcSend(cmd btcjson.Cmd) (btcjson.Reply, error) {
+	username, password, err := nc.getAuth()
+	if err != nil {
+		return btcjson.Reply{}, err
+	}
+
+	return btcjson.RpcSend(username, password, nc.Server, cmd)
 }
 
 // Query the Namecoin daemon for a Namecoin domain (e.g. d/example).
@@ -42,7 +66,7 @@ func (nc *Conn) Query(name string) (v string, err error) {
 		return "", err
 	}
 
-	r, err := btcjson.RpcSend(nc.Username, nc.Password, nc.Server, cmd)
+	r, err := nc.rpcSend(cmd)
 	if err != nil {
 		return "", err
 	}
@@ -81,7 +105,7 @@ func (nc *Conn) Sync(hash string, count int, wait bool) ([]extratypes.NameSyncEv
 		return nil, err
 	}
 
-	r, err := btcjson.RpcSend(nc.Username, nc.Password, nc.Server, cmd)
+	r, err := nc.rpcSend(cmd)
 	if err != nil {
 		return nil, err
 	}
@@ -112,7 +136,7 @@ func (nc *Conn) CurHeight() (int, error) {
 		return 0, err
 	}
 
-	r, err := btcjson.RpcSend(nc.Username, nc.Password, nc.Server, cmd)
+	r, err := nc.rpcSend(cmd)
 	if err != nil {
 		return 0, err
 	}
@@ -140,7 +164,7 @@ func (nc *Conn) Filter(regexp string, maxage, from, count int) (names []extratyp
 		return nil, err
 	}
 
-	r, err := btcjson.RpcSend(nc.Username, nc.Password, nc.Server, cmd)
+	r, err := nc.rpcSend(cmd)
 	if err != nil {
 		return nil, err
 	}
@@ -168,7 +192,7 @@ func (nc *Conn) Scan(from string, count int) (names []extratypes.NameFilterItem,
 		return nil, err
 	}
 
-	r, err := btcjson.RpcSend(nc.Username, nc.Password, nc.Server, cmd)
+	r, err := nc.rpcSend(cmd)
 	if err != nil {
 		return nil, err
 	}

server/cookiefile.go

@@ -0,0 +1,59 @@
+package server
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+	"time"
+)
+
+func readCookieFile(path string) (username, password string, err error) {
+	b, err := ioutil.ReadFile(path)
+	if err != nil {
+		return
+	}
+
+	s := strings.TrimSpace(string(b))
+	parts := strings.SplitN(s, ":", 2)
+	if len(parts) != 2 {
+		err = fmt.Errorf("malformed cookie file")
+		return
+	}
+
+	username, password = parts[0], parts[1]
+	return
+}
+
+func cookieRetriever(path string) func() (username, password string, err error) {
+	lastCheckTime := time.Time{}
+	lastModTime := time.Time{}
+
+	curUsername, curPassword := "", ""
+	var curError error
+
+	doUpdate := func() {
+		if !lastCheckTime.IsZero() && time.Now().Before(lastCheckTime.Add(30*time.Second)) {
+			return
+		}
+
+		lastCheckTime = time.Now()
+
+		st, err := os.Stat(path)
+		if err != nil {
+			curError = err
+			return
+		}
+
+		modTime := st.ModTime()
+		if !modTime.Equal(lastModTime) {
+			lastModTime = modTime
+			curUsername, curPassword, curError = readCookieFile(path)
+		}
+	}
+
+	return func() (username, password string, err error) {
+		doUpdate()
+		return curUsername, curPassword, curError
+	}
+}

server/server.go

@@ -39,12 +39,13 @@ type Config struct {
 	ZonePublicKey  string `default:"" usage:"Path to the DNSKEY ZSK public key file; if one is not specified, a temporary one is generated on startup and used only for the duration of that process"`
 	ZonePrivateKey string `default:"" usage:"Path to the ZSK's corresponding private key file"`
 
-	NamecoinRPCUsername string `default:"" usage:"Namecoin RPC username"`
-	NamecoinRPCPassword string `default:"" usage:"Namecoin RPC password"`
-	NamecoinRPCAddress  string `default:"localhost:8336" usage:"Namecoin RPC server address"`
-	CacheMaxEntries     int    `default:"100" usage:"Maximum name cache entries"`
-	SelfName            string `default:"" usage:"The FQDN of this nameserver. If empty, a psuedo-hostname is generated."`
-	SelfIP              string `default:"127.127.127.127" usage:"The canonical IP address for this service"`
+	NamecoinRPCUsername   string `default:"" usage:"Namecoin RPC username"`
+	NamecoinRPCPassword   string `default:"" usage:"Namecoin RPC password"`
+	NamecoinRPCAddress    string `default:"localhost:8336" usage:"Namecoin RPC server address"`
+	NamecoinRPCCookiePath string `default:"" usage:"Namecoin RPC cookie path (if set, used instead of password)"`
+	CacheMaxEntries       int    `default:"100" usage:"Maximum name cache entries"`
+	SelfName              string `default:"" usage:"The FQDN of this nameserver. If empty, a psuedo-hostname is generated."`
+	SelfIP                string `default:"127.127.127.127" usage:"The canonical IP address for this service"`
 
 	HTTPListenAddr string `default:"" usage:"Address for webserver to listen at (default: disabled)"`
 
@@ -78,6 +79,10 @@ func New(cfg *Config) (s *Server, err error) {
 		},
 	}
 
+	if s.cfg.NamecoinRPCCookiePath != "" {
+		s.namecoinConn.GetAuth = cookieRetriever(s.cfg.NamecoinRPCCookiePath)
+	}
+
 	if s.cfg.CanonicalNameservers != "" {
 		s.cfg.canonicalNameservers = strings.Split(s.cfg.CanonicalNameservers, ",")
 		for i := range s.cfg.canonicalNameservers {